Method of forming envelopes



April 11, 1939. J. J. SHEA ET AL METHOD OF FORMING ENVELOPES Filed April 22, 1936 Jimes J fikea mgr/zfir any fifl Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE METHOD OF FORMING ENVELOPES Application April 22, 1936, Serial No. 75,766

4 Claims.

The invention relates to the formation of envelopes cut from a web and particularly to a method by which wide variation in the shapes of the sealing and bottom closure flaps may be 5 obtained.

In the formation of envelopes from a web, (this type of envelope being substantially cheaper to produce than envelopes formed from die-cut blanks), the web is passed through a machine which applies gum along one of the edges of the web, preparatory to formation of the longitudinal seams of the envelopes. The machine notches out the outer edges of the web for forming the side flaps of the envelope which are then folded in and overlapped as the web continues its movement through the machine. Each partially formed envelope is severed from the web by a transverse out which defines the shape of the sealing flap of one envelope and the bottom flap of the adjacent envelope. The bottom flap is folded over and secured to the back wall of the envelope, preferably after the envelope has been severed from the web. One example of a machine for forming envelopes in this manner is disclosed in the Sanders Patent #1,169,l97, dated January 25, 1916.

This mode of formation of the envelope produces an entirely satisfactory and inexpensive envelope. There is, however, the objection that the size and shape of both the sealing and bottom closure flaps is limited and controlled by the transverse out which severs the envelope from the web. Thus, in order that the bottom flap may be satisfactorily attached to the side wall of the envelope, and in order that both flaps may have a not unattractive shape, the transverse cut must be substantially at right angles to the web. If the out is on a curved or arcuate line, to produce a convex seal flap, it will not merge with the notches of the web, and furthermore, the bottom flap, of necessity, will then be concave.

One of the principal objects of the present invention is to avoid the objection noted above by producing a Web-cut envelope having a sealing flap of any desired shape and size, independently of the shape and size of the bottom flap. To this end, the formation of the envelope involves the step of cutting the sealing flap to the desired shape during the movement of the envelope through the machine by a transverse cut made either simultaneously with, or subsequent to the severing of the envelope from the web.

During the formation of web-type envelopes, and especially in the use of webs of regenerated cellulose, it is practically impossible to formthe opposed notches in the opposite edges of the web in such a manner that a subsequent transverse cut for severing the partially completed envelope fro-m the web may produce rounded corners on the envelope flaps. This difficulty arises from the impossibility of mechanically forming notches having reentrant angles in the material forming the web during its movement through the machine. As a result, the end flaps of the envelope are invariably provided with square cornered flaps, which, although satisfactory in use, are not as neat in appearance as a flap having rounded corners. A further object of the present invention is accordingly to provide for the formation of p web-cut envelopes having rounded corners on the end flaps thereof.

Other and further objects and advantages of the invention will more fully appear from the following detailed description taken in connection with the accompanying drawing, in which Fig. l is a diagrammatic plan view of a web from which envelopes are cut, showing the successive steps in the formation of an envelope.

Fig. 2 is a diagrammatic showing of a mechanism for performing the several steps of the method.

Fig. 3 is a diagrammatic plan view similar to Fig. 1, showing the formation of a different style of envelope.

Fig. 4 is an enlarged view of an envelope pro-- duced from the web of Fig. 1.

Fig. 5 is an enlarged view of an envelope formed from the web of Fig. 3.

Like reference characters refer to like parts in the different figures. 3

With reference first to Fig. l, the envelope is formed from a web I of any desired material, such as paper, or, in the manufacture of transparent envelopes, from a web of regenerated cellulose. envelope together with the width of the side flaps, as will be apparent. The web is first provided with notches 2 in the opposite edges thereof, these notches being preferably spaced apart a distance slightly greater than the length of the completed envelope including the end flaps. Each notch is in the form substantially of a U with an additional small U-shaped notch 3 in the base of the main notch. The out which forms the notches 2 and 3 is continuous having no sharp corners and the intersection of the second notch 3 with the main notch is also along an arcuate line to make possible the formation of these notches as the web passes between opposed rollers, one of which is provided with a cutting blade. The

This web is thewidth of the completed opposite side edges of the main notch diverge toward the edges of the web, especially when the web is of regenerated cellulose, to make the formation of a notch easier, as will be apparent from Figs. 4 and 5.

During the formation of the envelope from the web a strip of adhesive 4 is applied to one side of the web adjacent one edge thereof for the purpose of holding the opposite side flaps 5 of the envelope together. Each of the side flaps 5 is defined by adjacent notches 2 which, as will be apparent, extend into the web a distance substantially equal to the width of the side flaps.

After the adhesive is applied, the side flaps 5 on opposite edges of the web are turned inwardly, as at 6, into overlapping relation to the central portion of the web with their edges overlapping, as at I. In this position. of the flaps, the adhesive 4 is located between the overlapping edges and holds: said flaps together. The partially completed envelope 8 is then severed from the web by a transverse cut 9, which, as will be apparent, is tangential to the arcuate side edges III of the second or additional notch 3. This cut defines the shape of the outer edge of the bottom closure flap which is. at the leading end of the envelope before removal from the web. The arcuate edges Ill provided by the notch 3 provide rounded corners on the bottom. closure flap, and the transverse cut 9, which may be straight across as shown, or may be on a relatively fiat arc, determines the shape of the outer edge of the bottom closure flap.

Either simultaneously with or subsequent to the transverse cut 9, a second transverse cut II is made to separate, from the partially completed envelope, a chip I2, the portion of the web between the outer edges of the bottom closure and sealing flaps of successive envelopes. The draw ing shows this transverse cut I I as being performed subsequently to the transverse cut I 0, although it will be apparent that they may both be made at the same time. The transverse cut I I is tangential to the arcuate edges I3 of the notches 3 opposite to the edges to which the cut 9 is tangential, and this cut II thereby defines the shape of the outer edge of the sealing flap, which may obviously be straight as in the showing of Fig. l, or may be of any other desired contour, depending upon the desired shape of the flap in the completed envelope.

The envelope is completed by applying a transverse strip of adhesive I4 adjacent to the bottom closure flap and folding the latter over against the side wall of the envelope. This may be performed at any time after the side flaps 5 are secured together, and, in the arrangement shown, is performed alter both the bottom closure flap and the sealing flap have been cut to the desired shape.

A structure by which the several steps in the process above described may be carried out is illustrated diagrammatically in Fig. 2. With reference to this figure, the web I passes first between opposed rolls I5 and IS, the former having cutting blades Il thereon corresponding in shape to the outer edges of the notches 2 and 3 in the opposite side edges of the web. Since the edges of the notches 2 and 3 have no sharp corners or reentrant angles, and since the opposite sides of the main notch diverge slightly, the formation of each notch is by a continuous out which assures a complete severing of the material in the notch from the remainder of the web.

and I9 by which adhesive is applied to one edge of the web, and opposed feed rolls 20 and 2| may be used to assure a positive movement of the web. Folding blades 22 turn the opposite side flaps 5 upwardly and inwardly into overlapping relation, and opposed rolls 23 and 24 apply pressure to the overlapping edges of the flaps to insure a positive adhesion of the flaps together. As the web passes between cutting rollers 25 and 26, the former having a cutting blade 21, the first transverse cut 9 is made to sever the partially completed envelope from the web. Pulling or feeding rolls 28 and 29 advance the partially severed envelope and feed it through opposed rollers 30 and 3|, the former having a cutting blade 32 for making the second transverse cut I I. Feeding rolls 33 and 34 then advance the en.- velope between opposed rollers 35 and 36, which apply the adhesive I4 and fold over the bottom closure flap. The exact construction of the rolls 35 and 36 is not important, since they do not of themselves form a part of the present invention. It may be noted that a machine incorporating certain of the features above referred to is fully disclosed in the Sanders Patent No. 1,169,197, dated January 25, 1916, above referred to.

A complete envelope formed by the above described method is shown in Fig. 4 on a larger scale, where it is clear that the opposite side flaps 5 overlap and are secured together, and that the lower end of the envelope is closed by folding the bottom closure flap 3'! upwardly against the side wall formed by the side flaps 5. The free edge 38 of the bottom closure flap is straight,

corresponding to the shape of the transverse cut 9, and the corners 39 of said flap are rounded, resulting from the arcuate side edges of the sec- 0nd notch 3 provided in the web during the formation of the envelope. Similarly, the sealing flap 40 has a straight outer edge 4| corresponding to the shape of the transverse cut II, and rounded corners 42, the latter being provided by the arcuate sides of the additional notch 3, above referred to. Since the edge 38 of the bottom closure flap is defined by the transverse cut 9, an

arcuate contour may be provided on the bottom closure flap by making the cut 9 arcuate. Similarly, since the transverse cut II defines the shape of the outer edge M of the sealing flap, this edge may be changed in shape by changing the shape of the transverse cut II.

With reference now to Fig. 3, the method disclosed produces an envelope whose sealing flap has an arcuate outer edge. The method is similar in general to that described in connection with Fig. 1. The web I is first provided with opposed notches 2' and additional smaller notches 3' projecting inwardly from the lower edges of the notches 2. It will be noted that the cut defining the notches 2' and 3' is a continuous curve, presenting no sharp corners and making possible the formation of these notches by a continuous cut. Adhesive 4 is applied to one edge of the web, and the opposite edges of the web are turned over into overlapping engagea ment with each other, the side flaps 5 defined by the notches 2 being secured together by the adhesive 4 to form a partially completed envelope 8'. The partially completed envelope 8 is severed from the web by a transverse cut 9' which defines the shape of the outer edge of the bottom closure flap 31'. The ends of the transverse cut 9' are tangential to the edges I0 of the notch 3, as will be apparent, to produce rounded corners on the bottom closure flap.

A second transverse cut II is made for the purpose of cutting the chip I2 away from the outer edge of the sealing flap, and the shape of the cut II is accordingly arcuate to form the arcuate outer edge of the sealing flap. After the sealing flap has been cut to shape, the envelope is completed in the usual manner by folding the bottom closure flap upwardly and securing it by suitable adhesive M to the side wall of the envelope.

With reference to Fig. 5, the completed envelope produced in the manner described in connection with Fig. 3, has the side flaps overlapping and secured together, and the bottom closure fiap 31' folded upwardly and over against the side flaps 5' and secured thereto. The outer edge 4| of the sealing flap 40 is arcuate and is, as, above stated, formed by the second transverse cut II. It is thus apparent that the sealing and bottom closure flaps may be provided with rounded corners, and that the shape of either the bottom closure or sealing flap may be controlled as desired by controlling the configuration of the transverse cuts by which the edges of the sealing and bottom closure flaps are defined.

From the foregoing, it will be apparent that the invention resides in the provision of notches in the opposite edges of the continuous web, these notches being spaced apart a distance slightly greater than the length of the envelope including the bottom closure and sealing flaps, with each notch formed by a out having a continuous contour with no sharp corners or reentrant angles. The side flaps which are defined by the notches are folded over and secured together, and the partially completed envelope is then severed from the web by a transverse out which defines the shape of the outer edge of one of the end flaps. A second transverse cut defines the shape of the outer edge of the opposite end flap, and this second cut is performed either simultaneously with or subsequent to the first transverse out. In the provision of rounded corners on the end flaps, the main notches provided in the opposite edges of the web have additional small notches with arcuate edges which define the outer corners of the end flaps, as best shown in Fig. l, with the subsequent transverse cuts tangential to the side edges of this notch. The additional notches form a part of the main notch and may be made at the same time the main notch is made.

We claim:

1. In the formation of a web-cut envelope, the steps which involve the provision of notches in opposite edges of the web, spaced apart a distance slightly greater than the length of the envelope including the end flaps, each notch having an additional small notch providing substantially arcuate edges at the base of the main notch, making a transverse cut across the web to sever the partially completed envelope from the web and define the outer edge of one of the end flaps, said out being substantially tangential to the corresponding arcuate edges of the opposide additional notches, and making a second transverse cut substantially tangential to the opposite arcuate edges of the notches, thereby defining the outer edge of the opposite end fiap.

2. In the formation of a web-cut envelope, the steps which involve the provision of notches in opposite edges of the web, spaced apart a distance slightly greater than the length of the envelope including the end flaps, each notch having an additional small notch providing substantially arcuate edges at the base of the main notch, making a transverse cut across the web to sever the partially completed envelope from the web and define the outer edge of one of the end flaps, said out being substantially tangential to the corresponding arcuate edges of the opposite additional notches, and making a second transverse cut substantially tangential to the opposite arcuate edges of the notches, thereby defining the outer edge of the opposite end flap, the two adjacent cuts located between successive envelopes in the web being spaced from each other.

3. In the formation of a web-cut envelope, in which the opposite edges of the web are notched to define side flaps which are subsequently folded into over-lapping relation and secured together and in which the envelope is severed from the web by a transverse cut, the bottom closure flap being folded over and secured tothe back wall of the envelope, the steps which involve the formation of the edge notches with arcuate corners and with integral additional notches having substantially arcuate edges and located at the base of the edge notches, and subsequently cutting the web transversely along spaced lines substantially tangential to the opposite arcuate edges of the additional notches to form thereby the outer edges of the end flaps of the envelope.

4. In the formation of a web cut envelope, the steps which involve notching the web at opposite sides thereof to define side flaps, each notch including an additional small notch having a continuous substantially arcuate edge and cated at the base of the main notch, severing a partially completed envelope from the web by a transverse cut substantially tangential to the arcuate edges of said small notches, and making a second transverse cut to remove excess web material between successive envelopes in the web, the adjacent first and second transverse cuts between successive envelopes in the web being spaced from each other throughout their length whereby the excess web material between successive envelopes is one continuous piece.

JAMES J. SHEA. g WILLIAM F. IRRGANG. 

